What is the Difference Between Cephalopods and Gastropods?

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Cephalopods and gastropods are two classes of invertebrate animals belonging to the phylum Mollusca. They have some similarities, such as having a muscular foot and a coiled shell, but they also have several key differences:

  1. Habitat: Cephalopods are strictly marine animals, including squid, octopuses, cuttlefish, and chambered nautiluses. Gastropods, on the other hand, can be found in various habitats, including terrestrial, marine, and freshwater environments. They include snails, conchs, abalones, whelks, sea slugs, and garden slugs.
  2. Diet: Cephalopods are carnivorous, feeding on fish, crustaceans, worms, and other mollusks. Gastropods have a more diverse diet, with some species being herbivores, detritivores, grazers, scavengers, browsing, or carnivorous.
  3. Shell: Gastropods typically have hard, external shells for protection. Cephalopods can have shells, but they are chambered and usually internalized, with the exception of some nautilus species.
  4. Symmetry: Cephalopods have a bilaterally symmetrical body, while gastropods have a body with asymmetrical due to torsion.
  5. Nervous System: Cephalopods have a more complex and developed nervous system compared to gastropods.
  6. Circulatory System: Cephalopods have a closed circulatory system, while gastropods have an open circulatory system.

In summary, cephalopods and gastropods are two distinct classes of mollusks with different habitats, diets, shell structures, body symmetries, nervous systems, and circulatory systems.

Comparative Table: Cephalopods vs Gastropods

Here is a table comparing the differences between cephalopods and gastropods:

Feature Cephalopods Gastropods
Class Cephalopoda Gastropoda
Habitat Strictly marine (except Atlantic brief squid) Marine, freshwater, and terrestrial habitats
Number of Species 650 to 700 extant species Over 62,000 described species
Examples Squid, cuttlefish, octopus Snails, slugs, conchs, abalones, whelks, sea slugs
Shell Internal (cuttlebone) or absent (octopuses) External (limpet, conch) or internal (snail)
Circulatory System Closed Open
Nervous System More complex Less complex
Venom Some cephalopods are venomous Uncommon
Lifestyle Prey on other marine life (active predators) Most are herbivores or detritivores; some are carnivorous
Reproduction Lay large yolky eggs or give birth to live young Lay small yolky eggs or give birth to live young

Cephalopods include squid, cuttlefish, and octopuses, while gastropods include snails, slugs, conchs, abalones, whelks, and sea slugs. The main differences between cephalopods and gastropods include their habitats, number of species, shell structure, circulatory system, nervous system, and lifestyle.